lecture 1: major networking concepts: a review dr. najla al-nabhan

Lecture 1: Major Networking Concepts: a Review

Dr. Najla Al-Nabhan

Najla Al-Nabhan Spring 2014-1435 lecture1:Revision

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Lecture Outline

Computer Networks: definition, concepts, uses, issues, hardware, software, etc.

Networks Classification Type of Transmission Technology: Point-to-point

and Broadcast Networks. Scale: PAN, LAN, MAN, and WAN.

Reference Models OSI Reference Model TCP/IP Reference Model


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What is a Computer Network? A computer network is a group of interconnected

computers.

It allows computers to communicate with each other to share resources and information.

Two computers are set to be interconnected if they are able to exchange messages between each other.

Connection can be through copper wires, fiber optics, microwaves, infrared, satellite, etc.


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What is a Computer Network? Definition: A Computer network is a collection of

computing devices with the required software and hardware that enable them to communicate and share resources.

An example of network components

Protocols , Standards, etc.

Modem, PCs, Routers, Switches, Wires, etc.


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Uses of Computer Networks

Sharing resource is the main objective of computer network.

Resources include: (information, software and hardware)

Wide range of networks applications: Business applications. Scientific applications Home applications Social Applications Mobile applications


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Networks Classification

Two Major Taxonomies:

1. Transmission Technology Broadcast Networks Point-to-Point Networks

2. Scale Personal Area Network (PAN) Local Area Network (LAN) Metropolitan Area Network (MAN) Wide Area Network (WAN) Internet


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Point-to-Point Networks Point-to-point links connect individual pairs of

machines. To go from the source(sender) to the

destination(receiver), messages may visit one or more intermediate machines before it reaches the destination machine.

Often multiple routes, of different lengths, are possible, so finding good ones is important in point-to-point networks.

Point-to-point transmission with exactly one sender and exactly one receiver is sometimes called unicasting. (1-to-1)


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Point-to-Point Networks: Examples


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Broadcast Networks

A single communication channel is shared by all machines in the network.

Short messages (called packets) 1-to-Many communication: A packet is sent by

the “source” machine and received by more than one machine;

Broadcasting: Sending a packet to all the machines in the network.

Multicasting? Sending a packet to a group of machines in the network.


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Broadcast Networks: Examples


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SCALE(SIZE) BASED NETWORK CLASSIFICATION

1. PAN

2. LAN

3. MAN

4. WAN

5. Internet


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Netw

ork size in

creases


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Personal Area Network (PAN) computer network organized around an

individual person.

PAN involves a computer, a cell phone..etc Using Bluetooth and USB often used to link

this kind of networks.

Communication Technology: Wired Wireless (WPAN):(Bluetooth, infrared)


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Local Area Network (LAN)

A LAN is a privately owned network that operates within and nearby a single building like a home, office or factory.

The connection must be high speed and inexpensive.

Size: few kilometers.


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In Wireless LAN, each computer talks to a device, called an AP(Access Point), wireless router, or base station. This device helps in transferring packets between the wireless computers and also between them and the Internet.

Wired LAN Wireless LAN


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Advantages Easy to share devices (printers, scanners, external drives) Easy to share data files (homework, pictures) Cost of LAN setup is low.

Disadvantages Power: a good LAN is required to be on all the times. Security: each computer and device become another point of

entry for undesirables. If all computers are running at the same time, the speed might be

reduced. Covers limited area.


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Metropolitan Area Network (MAN) A metropolitan area network (MAN) is a high-

speed network that connects local area networks in a metropolitan area

It covers a city.

Examples: A network that handles the bulk of communication

activities across a city or town. The cable television networks available in many cities.


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Metropolitan Area Network (MAN)

A MAN based on cable TV.A MAN covering a university campus, hospital and other .


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Metropolitan Area Network (MAN) Advantages

Efficiency and shared access. All the computers residing in the same area have an equal

chance to access the network.

Disadvantages It can be costly(hardware, software, support, etc.) Security problems As the network consists of many computers over the span of a

city, the connection can become quite slow.


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Wide Area Network (WAN)

A wide area network (WAN) is a network that covers a large geographic area (such as a city, country, or the world) using a communications channel that combines many types of media such as telephone lines, cables, and radio waves.


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A wide area network (WAN) is a network that covers a large geographic area (such as a city, country, or the world) using a communications channel that combines many types of media such as telephone lines, cables, and radio waves.


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The Internet is the world’s largest WAN.



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Advantages Increased efficiency. Ease of communication.

Disadvantages Security problems. Training costs. Maintenance problems: Large enterprises will dedicate staff to

maintain their WAN.


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Common Networking Terminologies Wi-Fi (Wireless Fidelity)

A wireless technology that connects computers without cables

Access Point (AP) A device (base station) that connects wireless devices

together Usually connected to a wired-network

Hotspot The area covered by wireless access points

Satellite A broadcast system that provides digital data transmission

over satellites


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Intranet vs. Internet

Intranet A private network that is contained within an

enterprise Could be LANs and WANs

Internet A public network of networks (a WAN)

Both are using TCP/IP

lecture 1: major networking concepts: a review dr. najla al-nabhan

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